Back to DRIVERS page

AVR UC3 Series Software Framework: AST Driver

Copyright © 2009 Atmel Corporation

Introduction

The AST (Asynchronous Timer) enables periodic interrupts and events, as well as interrupts and events at a specified time in the future. The AST consists of a 32-bit prescaler which feeds a 32bit up-counter. The prescaler can be clocked from four different clock sources, including the lowpower 32 KHz clock, which allows the AST to be used as a real-time timer with a maximum timeout of more than 100 years. Also, the PB clock or a generic clock can be used for high-speed operation, allowing the AST to be used as a general timer.

The AST can generate periodic interrupts and events from output from the prescaler, as well as timer alarm interrupts and events, which can trigger at any counter value. Additionally, the timer can trigger an overflow interrupt and event, and be reset on the occurrence of any timer alarm.

This allows periodic interrupts and events at very long and accurate intervals.

The AST has been designed to meet the system tick and Real Time Clock requirements of most embedded operating systems.

 

AST Driver

The driver is composed of ast.c and ast.h.

 

Example are available:

How to use the AST in calendar mode.

How to use the periodic alarm to wake-up from static sleep mode.

 


AVR is a registered trademark of Atmel Corporation.

>